Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Descent into Avernus

At the beginning of your upkeep, put two descent counters on Descent into Avernus. Then each player creates X Treasure tokens and Descent into Avernus deals X damage to each player, where X is the number of descent counters on Descent into Avernus.

Solphim, Mayhem Dominus

If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals double that damage to that player or permanent instead.
{1}{R/P}{R/P}, Discard two cards: Put an indestructible counter on Solphim, Mayhem Dominus. ({R/P} can be paid with either {R} or 2 life.)

Harmonic Prodigy

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
If an ability of a Shaman or another Wizard you control triggers, that ability triggers an additional time.

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek the Merciless deals damage equal to that spell's mana value to any target.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Mana Geyser

Add {R} for each tapped land your opponents control.

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Basilisk Collar

Equipped creature has deathtouch and lifelink.
Equip {2}

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Grafted Exoskeleton

Equipped creature gets +2/+2 and has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever Grafted Exoskeleton becomes unattached from a permanent, sacrifice that permanent.
Equip {2}

Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Sol Ring

Dark Ritual

Dingus Staff

Whenever a creature dies, Dingus Staff deals 2 damage to that creature's controller.

Terminate

Destroy target creature. It can't be regenerated.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Possibility Storm

Whenever a player casts a spell from their hand, that player exiles it, then exiles cards from the top of their library until they exile a card that shares a card type with it. That player may cast that card without paying its mana cost. Then they put all cards exiled with Possibility Storm on the bottom of their library in a random order.